Air Plan Approval; Virginia; Revision to the Regulatory Definition of Volatile Organic Compound

ENVIRONMENTAL PROTECTION AGENCY <CFR>40 CFR Part 52</CFR> <DEPDOC>[EPA-R03-OAR-2025-0225; FRL-12836-01-R3]</DEPDOC> <SUBJECT>Air Plan Approval; Virginia; Revision to the Regulatory Definition of Volatile Organic Compound</SUBJECT> <HD SOURCE="HED">AGENCY:</HD> Environmental Protection Agency (EPA). <HD SOURCE="HED">ACTION:</HD> Proposed rule. <SUM> <HD SOURCE="HED">SUMMARY:</HD> The Environmental Protection Agency (EPA) is proposing to approve a state implementation plan (SIP) revision (Revision A23) submitted by the Commonwealth of Virginia. This revision pertains to an amendment made to the definition of volatile organic compound (VOC) in the Virginia Administrative Code (VAC) to align with the EPA's regulatory definition of VOC. The EPA is approving this revision to update the definition of VOC in the Virginia SIP. </SUM> <EFFDATE> <HD SOURCE="HED">DATES:</HD> Written comments must be received on or before October 27, 2025. </EFFDATE> <HD SOURCE="HED">ADDRESSES:</HD> Submit your comments, identified by Docket ID No. EPA-R03-OAR-2025-0225 at <E T="03">www.regulations.gov,</E> or via email to <E T="03">gordon.mike@epa.gov.</E> For comments submitted at <E T="03">Regulations.gov,</E> follow the online instructions for submitting comments. Once submitted, comments cannot be edited or removed from <E T="03">Regulations.gov.</E> For either manner of submission, the EPA may publish any comment received to its public docket. Do not submit electronically any information you consider to be confidential business information (CBI) or other information whose disclosure is restricted by statute. Multimedia submissions (audio, video, etc.) must be accompanied by a written comment. The written comment is considered the official comment and should include discussion of all points you wish to make. The EPA will generally not consider comments or comment contents located outside of the primary submission ( <E T="03">i.e.,</E> on the web, cloud, or other file sharing system). For additional submission methods, please contact the person identified in the <E T="02">For Further Information Contact</E> section. For the full EPA public comment policy, information about CBI or multimedia submissions, and general guidance on making effective comments, please visit <E T="03">www.epa.gov/dockets/commenting-epa-dockets.</E> <FURINF> <HD SOURCE="HED">FOR FURTHER INFORMATION CONTACT:</HD> Sarah McCabe, Planning & Implementation Branch (3AD30), Air & Radiation Division, U.S. Environmental Protection Agency, Region III, 1600 John F. Kennedy Boulevard, Philadelphia, Pennsylvania 19103. The telephone number is (215) 814-5786. Ms. McCabe can also be reached via electronic mail at <E T="03">mccabe.sarah@epa.gov.</E> </FURINF> <SUPLINF> <HD SOURCE="HED">SUPPLEMENTARY INFORMATION:</HD> On December 20, 2024, the Commonwealth of Virginia, through the Virginia Department of Environmental Quality (VADEQ), submitted a revision to its SIP (Revision A23). Revision A23 requests to update the definition of VOC in the Virginia SIP (9 VAC 5-10-20 (General Definitions)). Specifically, this amendment adds <E T="03">trans-</E> 1,1,1,4,4,4-hexafluorobut-2-ene (also known as and hereafter referred to as HFO-1336mzz(E); Chemical Abstracts Service [CAS] number: 66711-86-2) as a compound excluded from the regulatory definition of VOC to align with the EPA's February 8, 2023 (88 FR 8226) final rule updating the EPA's regulatory definition of VOC in 40 CFR 51.100(s). The EPA's rulemaking added HFO-1336mzz(E) to the list of compounds excluded from the EPA's regulatory definition of VOC. <HD SOURCE="HD1">I. Background</HD> VOCs are organic compounds of carbon that, in the presence of sunlight, react with sources of oxygen molecules, such as nitrogen oxides (NO <E T="52">X</E> ) and carbon monoxide (CO), in the atmosphere to produce tropospheric ozone, commonly known as smog. Common sources that may emit VOCs include paints, coatings, housekeeping and maintenance products, and building and furnishing materials. Outdoor emissions of VOCs are regulated by the EPA primarily to prevent the formation of ozone. VOCs have different levels of volatility, depending on the compound, and react at different rates to produce varying amounts of ozone. VOCs that are non-reactive or of negligible reactivity to form ozone react slowly and/or form less ozone; therefore, reducing their emissions has limited effects on local or regional ozone pollution. Section 302(s) of the CAA specifies that the EPA has the authority to define the meaning of VOC and what compounds shall be treated as VOCs for regulatory purposes. It is the EPA's policy that organic compounds with a negligible level of reactivity should be excluded from the regulatory definition of VOC in order to focus control efforts on compounds that significantly affect ozone concentrations. The regulatory definition of VOC as well as a list of compounds that are designated by the EPA as negligibly reactive can be found at 40 CFR 51.100(s). Virginia has amended the definition of VOC to match EPA actions multiple times in their SIP. On August 1, 2016, EPA promulgated a final rule revising the regulatory definition of VOC in 40 CFR 51.100(s) to add HFE-347pcf2 to the list of compounds excluded from the regulatory definition of VOC (81 FR 50330). This action was based on the EPA's consideration of the compound's negligible reactivity and low contribution to ozone as well as the low likelihood of risk to human health or the environment. The EPA's rationale for this action is explained in more detail in the final rule for this action. <E T="03">See</E> 81 FR 50330 (August 1, 2016). On March 13, 2018, the EPA approved revisions to the Virginia SIP, excluding HFE-347pcf2 from the regulatory definition of VOC and removing recordkeeping and reporting requirements for t-butyl acetate. These revisions matched actions EPA had previously taken. <E T="03">See</E> 83 FR 10788. On November 30, 2016, the Chemours Company submitted a petition to the EPA requesting that <E T="03">trans-</E> 1,1,1,4,4,4-hexafluorobut-2-ene (HFO-1336mzz(E)) be exempted from the Federal regulatory definition of VOC. If it can be demonstrated that a particular VOC is “negligibly reactive” that is, if it can be shown that a VOC is not as reactive and therefore does not have a significant effect on ground-level (tropospheric) or upper-level (stratospheric) ozone, then the EPA may remove that compound from the definition of VOC. The petition was based on the argument that HFO-1336mzz(E) has low reactivity and may be used in a variety of applications in foam expansion or blowing agents where it has significant performance and energy-saving advantages. After scientific review and public comment, the EPA took final action on February 8, 2023, to respond to the petition by exempting HFO-1336mzz(E) from the Federal regulatory definition of VOC in 40 CFR 51.100(s) (88 FR 8226, February 8, 2023). This action was based on consideration of the compound's low contribution to tropospheric ozone and the low likelihood of risk to human health or the environment, including stratospheric ozone depletion and toxicity. This delisting became effective on April 10, 2023. <HD SOURCE="HD1">II. Summary of SIP Revision and EPA Analysis</HD> On December 20, 2024, VADEQ submitted Revision A23, a SIP revision amending the definition of VOC in 9 VAC 5-10-20 (General Definitions). VADEQ submitted this revision to align with the EPA's current regulatory definition of VOC in 40 CFR 51.100(s) and add HFO-1336mzz(E) to the list of compounds excluded from the regulatory definition of VOC. The Virginia State Air Pollution Control Board adopted the revision on September 13, 2023, the revision was published in the Virginia Register of Regulations on February 26, 2024, and the revision became effective on April 11, 2024. In this action, the EPA is proposing that Virginia's amendment to the definition of VOC in 9 VAC 5-10-20 is in accordance with the EPA's regulatory changes to the definition of VOC in 40 CFR 51.100(s) and are therefore approvable for the Virginia SIP in accordance with CAA section 110. On February 8, 2023, the EPA made the determination that HFO-1336mzz(E) is of negligible reactivity and therefore has low contributions to tropospheric ozone as well as a low likelihood of risk to public health or the environment (88 FR 8226). Removing this compound from the definition of VOC in the Virginia SIP will not interfere with attainment of any NAAQS, reasonable further progress, or any other requirement of the CAA, as explained in EPA's rationale in the final rule for that action (88 FR 8226, February 8, 2023). The addition of HFO-1336mzz(E) to the list of compounds excluded from the regulatory definition of VOC is in accordance with CAA section 110(l). <HD SOURCE="HD1">III. Proposed Action</HD> The EPA is proposing to approve Revision A23, submitted on December 20, 2024 by VADEQ, as a revision to the Virginia SIP, because the submission meets the requirements of CAA section 110. Revision A23 adds HFO-1336mzz(E) to the list of compounds excluded from the regulatory definition of VOC in 9 VAC 5-10-20. The EPA is soliciting public comments on the issues discussed in this proposed rulemaking. These comments will be considered before taking final action. <HD SOURCE="HD1">IV. General Information Pertaining to SIP Submittals From the Commonwealth of Virginia</HD> In 1995, Virginia adopted legislation that provides, subject to certain conditions, for an environmental assessment (audit) “privilege” for voluntary compliance evaluations performed by a regulated entity. The legislation further addresses the relative burden of proof for parties either asserting the privilege or seeking disclosure of documents for which the privilege is claimed. 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